Small doesn’t necessarily mean safe. Low-horsepower gasoline engines like those used on pressure washers, portable waterjetters, air compressors, and generators produce carbon monoxide in exhaust just as larger engines do. When used for work indoors or in semi-enclosed spaces, they need to be treated with care.
“Carbon monoxide (CO) can rapidly accumulate even in areas that appear to be well ventilated and build up to dangerous or fatal concentrations within minutes,” according to a fact sheet from the National Institute for Occupational Safety and Health. If you doubt it, consider these examples cited by NIOSH:
A plumber used a gasoline-powered concrete saw
